Stay-bolt for boilers.



B. E. D. STAFFORD. STAY BOLT FOR BOILERS.

APPLloATIoN FILED DEG.13, 1911.

L. Patented 0@s.29,1912.

'MAW/ENT@ 6706;

narrany s'rarerarnnr orari it;

BENJAMIN E. D. STAFFORD, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO FLLNNERY BOLT COMPANY, OF PITTSBURGH, PENNSYLVANIA.

' STAY-Bom ron. BorLEns.

LMZES.

Specification of Letters Patent.

' Patented (het. ZQWLZ.

T0 all whom t may concern Be it known that l, BENJAMIN E. D. Snrrom), of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in Stay-Bolts for Boilers and I do hereby declare the following to be a full, clear, and exact description ofthe invention, such as will enable others skilled in the art to which it appertains to make and use the same.

My invention relates to an improvement in stay bolts for boilers, and it consists in the details of construction as will be mort fully described and pointed out in the claims.

ln the accompanying drawings, Figure l is a view partly in section and partly in elevation, showing the bolt applied to the inner and outeri sheets of a boiler, and Fig. 2 is a view'in plan of the same.

l represents the bolt provided with a head 2, the portion thereof which yrests on the seat 3 of the sleeve or bushing a, being concave as at 5, while the portion 6 thereof'- above the concave bearing portion is convea, and preferably the segment of a sphere the extreme top of the head being in the form of an angular boss 7 adapted tol be engaged by a wrench.

Secured within the outer sheet 8 of the boiler, is the sleeve or bushing Ll, threaded ex-A ternally for engagement wit-h said outer sheet' 8and preferably made slightly tapering so as to form a steam tight joint. Thebore of the bushing or sleeve 4 below the seat 3, is con-j veX and flares outwardly from the seat 3 to its lower end, so as to provideffor the up and dislodging incrustation which forms thereon. The sleeve or bushing is provided above its Aconvex seat 3, with an annular seat or bearing 9, for the V-shaped or knife blade edge of the soft metal cap 10, which latter rests thereon and forms a housing for the head of the bolt and a closure for the sleeve or bushing. The cap may. be stamped or cast, and is made of copper or copper alloy or other comparatively soft metal, so that when clamped against its seat vwithin the sleeve or bushing 4, the knife blade edge of the cap will flatten out and form a perfect steam tight joint.l rlhe cap is concave on its inner face and is removed from the free movement of the latter,.and is provided centrally on its outer surface with an anguengaged by a wrench whereby the cap may be turned on its seat, before it is fully clamped in place, to clean its bearing sur-l face and also clean the seat or bearing 9 on the-bushing. The sleeve or bushing is at right anglesto and at the outer edge of the seat or bearing 9, which shoulder forms an abutment for the lower end of the cap and revents the latter from expanding or compressingaction of the nut 13. The upper end of the sleeve Aor bushing 4c is threaded internally to receive the lower end vof the externally threaded nut 13, which lat-ter has an annular shoulder lil adapted to rest. on upper dat surface l5 of the rim ofthe cap. This shoulder Mis in the vertical plane of the seator bearing 9 on the bushing, hence as the compressive strains are in al vertical plane, there is no stra-in tending to collapse the cap while under compression. The lower end of the nut extends down adjacent the outer side of the rim of the cap, and assists the shoulder 12 in preventing .any undue out-ward expanthenut overhangs the cap and protects the ing due to contact with the bolt when the of the inner sheet. rlhe boss 11 on the cap projects through and beyond the nut so as to be engaged by a wrench after the parts have obeen assembled.

- The cap 10 not only forms a closure for the bushing, or sleeve, but being of softer metal than the bushing and the nut, serves as a packing, thus dispensing with they use of a gasket or other packing, which in many forms of' bolts are necessary in order to secure a steam tight joint.

l make no claim in this application toa stay bolt structure comprising a. bolt having a head, a sleeve or bushing having an internal seatfor said head, a soft metal cap forming a closure for'the sleeve or bushing and a nut for locking the cap to the bushing, asthe same forms the subject mat-ter of lar, preferably rectangular boss l1, to be same against fracture or excessive stretch-` head of the bolt sufficiently to permit of the also provided with anannular shoulder 12,

bulging outwardly under the crushing or sion of the rim, while the upper portion of latter is forced outwardly by the expansion i my pending application No. 665,504 filed December 13th 1911.

lt is ,evident that many slight changes might be resorted to in the relative arrangement of parts shown and described withoutl departing from the spirit and scope of the claims annexed. Hence l would have it understood that l do not wish to confine rnyself 'except as required by the scope of said claims to the exact, construction and arrangement of parts shown and described, but

Having fully described my invention what I claim as new and desire to secure by Letters-Patent, is

l. A stay bolt structure comprising a bolt having a head, a sleeve or bushing having an internal seat for said head and also provided with an annular seat or bearing, and with an annular shoulder at the outer edge of said seat, a cap resting on said seat and supported laterally by said shoulder, and a nut having external threads engaging internal threads on the upper end of the sleeve or bushing and provided with an internal shoulder which bears against the top surface of the rim of the cap.

2. A stay bolt struct-ure comprising a bolt having a head, a sleeve or bushing having an internal seat for said head, and also pro-v vided with an annular shoulder at the outer edge of said seat, a soft metal cap having a Loaaase ll-shaped lower end resting on said seat and sustained laterally by said shoulder, and a nut having'external threads engaging internal threads on the upper end of the sleeve or bushing and provided with an interna-l shoulder which bears against the top surface of the rim of the cap, the said nut overhanging the rim-of said cap.

3. A stay bolt structure comprisino a bolt having a head the bearing surface of which is concave and the part thereof Vabove its bearings surface convex, a sleeve or bushing having a convex seat on which the concave surface of the bolt head rests, a removable cap resting on a seat on the bushing and forming a closure for the latter, and a nut y 'BENJAMIN E. D. STAFFURD.

Witnesses:

EDWIN S. RYoE, WM. L. MCNABB. 

